JPH0225786Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) This invention relates to a paper feeding device used in copying machines and recording devices.

(Prior Art) For example, in a copying machine, a paper feeding device is known that stacks and stores a large amount of copy paper (hereinafter referred to as "sheets") and separates and feeds the paper. Such a paper feeding device includes a sheet stacking table that can be raised and lowered to place sheets in a stack, an elevating mechanism that raises and lowers the sheet loading table, and a lifting mechanism that contacts the uppermost sheet of a bundle of sheets stacked on the sheet stacking table. A sheet sending roller that sends out the sheet in the sheet feeding direction, an upper separating roller that is arranged downstream of the sheet feeding roller in the sheet feeding direction and rotates in the sheet feeding direction, and a pair of the upper separating roller. has been completed,
It consists of a lower separation roller that is stopped during paper feeding. Then, when the elevating device lifts the sheet mounting table, the uppermost sheet of the stack of sheets stacked on the table is brought into contact with the sheet delivery roller. When the feed roller rotates in the sheet feeding direction in response to a paper feed command, the uppermost sheet is fed between the upper separation roller and the lower separation roller. At this time, the upper separation roller rotates in the sheet feeding direction, and the lower separation roller is stopped. Therefore, even if the feed roller sends out several sheets including the top sheet, the progress of the sheets other than the top sheet is blocked by the stopped separation lower roller, so only the top sheet is sent out. It is fed by the upper separation roller.

By the way, if a fed sheet gets stuck in the middle of its conveyance path, the operation of the apparatus is stopped to ensure the safety of the apparatus. At this time, the operation of the paper feeding device is also stopped. Further, the operation of the paper feeding device is also stopped when replenishing the sheets stored in the paper feeding device or when changing the type of sheet. Regardless of the cause of the stoppage of the paper feeding device, the sheet being fed or the sheet waiting is held between the upper separation roller and the lower separation roller. If the sheet mounting table is pulled out with the sheet sandwiched between the two rollers, the sandwiched sheet will be left behind inside the apparatus.
In particular, if a part of the sheet feeding device including the sheet loading table is pulled out horizontally in a direction perpendicular to the sheet feeding direction, sheets left inside the device will be damaged. On the other hand, when the paper feeding device is pulled out, since the uppermost sheet is in contact with the sheet feeding roller, it is necessary to separate the two. To this end, the sheet mounting table is lowered before the device is pulled out.

Conventionally, in order to prevent the sheet from being damaged, the lower separation roller is rotated in the opposite direction to the sheet feeding direction in conjunction with the operation of lowering the sheet loading table, and the upper separation roller and the lower separation roller are separated. It is known to release a sheet held in its mouth. By the way, the lifting mechanism that lifts and lowers the sheet mounting table is
The operating time varies depending on the height of the stacked sheets. When the maximum amount of sheets is loaded,
The descending time of the sheet loading table is short, but if only a small number of sheets are loaded, the descending time is relatively long. On the other hand, the length of the sheet held by the upper separation roller and the lower separation roller is approximately constant. Furthermore, the sheet delivery roller is designed to move up and down to some extent in order to provide a range of pressure contact force with the topmost sheet. For these reasons, the sheet sent back by the reversing lower separation roller may not be able to escape from between both rollers due to the resistance of the sheet delivery roller, or may become combed between the sheet delivery roller and the pair of separation rollers. There is a problem with this. In addition, if the amount of descent of the sheet loading table is small, the time required to reverse the lower separation roller will be shortened, so the lower separation roller will be turned off before the sheet held between the upper separation roller and the lower separation roller is completely released. There is a problem that the rotation stops, and in any case, the sheet held between both rollers becomes unusable.

(Purpose) The present invention was devised in view of the above-mentioned problems, and includes a rotation transmission delay mechanism in a part of the lower separation roller drive mechanism to ensure reliable operation regardless of the amount of descent of the sheet loading table. It is an object of the present invention to provide a paper feeding device capable of pulling back sheets.

(Structure) The present invention will be described in detail below based on the illustrated embodiments.

In FIG. 1, reference numeral 1 indicates a sheet mounting table on which sheets S are stacked and mounted. The leading ends of the sheets S are aligned by the front wall member 2. A sheet delivery roller 3 is arranged above the front end of the stacked sheets. This roller 3 is selectively driven to rotate in the direction indicated by the arrow by a drive means (not shown), and sends out the uppermost sheet in the sheet feeding direction a. In the sheet feeding direction a, on the downstream side of the roller 3, there is an upper separating roller 4.
and a lower separation roller 5 forming a pair therewith are respectively arranged. The upper separation roller 4 is rotationally driven in the direction indicated by the arrow by a drive source (not shown). A delivery roller support arm 7 is rotatably supported on the shaft 6 of the upper separation roller 4 . The sheet delivery roller 3 is rotatably supported by a support arm 7.
The lower limit of this roller 3 is regulated by a regulating member 8 that regulates the descending of the support arm 7 . The regulating member 8 is fixed to an immovable member.

The lower separation roller 5 is supported by a support shaft 9. At one end of the support shaft 9, as shown in FIG.
A reversing gear 11 is attached via a one-way clutch 10. This one-way clutch 10 cannot be rotated with respect to the roller even if an attempt is made to rotate it counterclockwise, but when the support shaft 9 is rotated clockwise, the roller can be rotated in the same direction. It acts on The lower separation roller 5 is pressed against the upper separation roller 4 by means not shown, but even if the upper separation roller 4 rotates, the lower separation roller 5 remains in a stopped state. A pair of sheet conveying rollers 12 is arranged downstream of these roller pairs.

In FIG. 2, the sheet mounting table 1 is connected to a lifting mechanism 13. As shown in FIG. The lifting mechanism 13 includes a drive motor 14, a worm 15, and a worm wheel 1.
6. It consists of a pulley 17 integrated with the worm wheel, and a wire 22 wound around this pulley 17 and other pulleys 18 to 21. Reference numeral 23 indicates a tension pulley. And pulley 1
The wires 24 and 25 in the portions extending between the wires 8 and 19 and between the pulleys 20 and 21 are fixed to the sheet mounting table 1. The sheet mounting table 1 has a drive motor 1
When the motor 4 rotates in the forward direction, it is raised, and when the same motor rotates in the reverse direction, it is lowered. This elevating mechanism 13 is attached to a casing (not shown).

A gear 27 is integrally provided on the shaft 26 of the pulley 19. The gear 27 includes a speed increasing gear train 28
A small diameter gear 29 located at one end of the two meshes with each other. Control gear 3 located at the other end of speed increasing gear train 28
An intermediate gear 32, which is always in mesh with the reversing gear 11, is meshed with the large diameter gear 31. This intermediate gear 32 is provided on the immovable side of the copying machine, and the speed increasing gear train 28 is attached to a housing (not shown) that can be freely pulled out from the copying machine.

The configuration of the control gear 30 will be explained based on FIG. 3. The figure shows the configuration of the rotation transmission delay mechanism, and one end surface of the large-diameter gear 31 has fan-shaped protrusions 33, 3.
4 and a tube shaft 35 are formed, and a small diameter gear 36 is fitted into the tube shaft 35 so as to be rotatable at a predetermined angle. Projections 37 and 38 are formed on the end face of the small diameter gear 36 and abut against the projections 33 and 34, respectively. As shown in FIG. 4, the protrusions 37 and 38 of the small diameter gear 36 can be positioned movably relative to the protrusions 33 and 34 of the large diameter gear 31. Causes a time lag.

The movement of the wire 22 when the sheet mounting table 1 is raised as shown by arrow b is transmitted to the small diameter gear 36 via the pulley 19 and gears 27, 29, 39, 40, and 41, and is Rotate clockwise. Therefore, when the sheet mounting table 1 is raised, the control gear 30 moves the protrusions 37 and 38 of the small diameter gear 36, as shown by the solid line in FIG.
It is placed in contact with the protrusions 33 and 34 of the large-diameter gear 31 in a counterclockwise direction. On the other hand, when the sheet mounting table 1 is being lowered, the sheet delivery roller 3 has been lowered to the lower limit position where the support arm 7 is engaged with the regulating member 8.

(Function and effect) When a sheet bundle S is loaded on the sheet loading table 1 pulled out from the copying machine main body and pushed into the main body, the leading end of the sheet bundle is located below the sheet delivery roller 3 and has a large diameter. The gear 31 meshes with the intermediate gear 32.

When the power of the copying machine is turned on, a sheet level detection means (not shown) is activated, and the elevating mechanism 13 is activated. When the drive motor 14 rotates normally, the sheet mounting table 1 is raised in the direction of arrow b (see FIG. 2) via the pulley and wire. Then, when the uppermost sheet collides with the sheet delivery roller 3 and the support arm 7 is slightly separated from the regulating member 8, the drive motor 14 is turned off. The rotation of the gear 27 when the elevating mechanism 13 raises the sheet platform 1 causes the control gear 30 to rotate counterclockwise via the speed increasing gear train. The mode of the control gear 30 at this time is as shown by the solid line in FIG. 4, with the small diameter gear 36 rotating the large diameter gear 31 counterclockwise. Therefore, the intermediate gear 32 meshing with the large-diameter gear 31 rotates the reversing gear 11 counterclockwise. This counterclockwise rotation of the reversing gear 11 is not transmitted to the support shaft 9 due to the presence of the one-way clutch 10. Therefore, the lower separation roller 5
remains in a stopped state. At this time, the lower separation roller 5 is brought into pressure contact with the upper separation roller 4.

Then, when a paper feeding command is issued, the transport roller pair 12, the upper separation roller 4, and the sheet delivery roller 3
start rotating in the directions indicated by the arrows (see Figure 1). The sheet delivery roller 3 sends out the uppermost sheet in the sheet feeding direction a. At this time, when a plurality of sheets including the uppermost sheet are sent out, the leading edge of the sheet bundle is bitten by the upper separation roller 4 and the lower separation roller 5. The next sheet and the following sheets are prevented from advancing by the stopped lower separation roller 5, but only the uppermost sheet receives the feeding force of the upper separation roller 4 and moves against the conveyance roller. Sent towards 12th. When the topmost sheet receives the feeding force from the conveying roller pair,
The transmission of driving force to the upper separation roller 4 and the sheet delivery roller 3 is released. After this, both rollers follow the advancing sheet.

The sheet whose advance was prevented by the lower separation roller 5 is slightly moved by friction with the advancing sheet, and the rear end of the advancing sheet is moved between the upper separation roller 4 and the lower roller. When it came out from between 5, the leading edge of the sheet that had been blocked was
It is held between both rollers 4 and 5. The above action can be repeated to feed the sheet.

When a signal such as a jam signal is output from the copying machine main body, a reverse rotation signal is input to the drive motor 14 to lower the sheet mounting table 1. The reason for lowering the sheet placing table 1 may be to replace or replenish the sheets on the sheet placing table 1. In this case, the reverse rotation signal to the drive motor 14 is inputted by manual operation.

At this time, the leading edge of the sheet is held between the upper separation roller 4 and the lower separation roller 5.

When the sheet mounting table 1 is lowered, the gear 2
7 rotates counterclockwise. The rotation of gear 27 is
The control gear 30 is increased in speed via the speed increasing gear train 28.
is transmitted to the small diameter gear 36, which rotates it counterclockwise.

The rotation of the small diameter gear 36 is caused by its protrusions 37 and 38.
is rotated idly until it engages with the protrusions 33 and 34 of the diameter gear 31, as shown by chain lines in FIG. 4, and then is transmitted to the large diameter gear 31.

After the elevating mechanism 13 starts operating, until the large-diameter gear 31 starts rotating, the engagement mode between the protrusions 33 and 34 and the protrusions 37 and 38, which are rotation transmission delay mechanisms, changes. A time lag will occur. This time is approximately equal to or slightly longer than the time required for the sheet delivery roller 3, which descends following the descent of the uppermost sheet, to be regulated to its lower limit by the regulation member 8.

Therefore, the rotation of the large diameter gear 31 is caused by the rotation of the intermediate gear 3.
2. When transmitted to the lower separating roller 5 through the reversing gear 11 to rotate it in the opposite direction to the sheet feeding direction a, the sheet feeding roller 3 is completely separated from the uppermost sheet. Therefore, the lower separation roller 5, which rotates in the opposite direction, sends back the sheet held between it and the upper separation roller 4 in the opposite direction to the sheet feeding direction. The upper separation roller 4 is rotated along with the roller 5 which rotates in reverse. In this case, the sheet being sent back is not subjected to any resistance by the sheet delivery roller 3, so it can be moved smoothly. The sheet feeding force by the lower separating roller 5 disappears as soon as the sheet leaves the roller, but most of the sheet is transferred to the descending sheet loading table 1.
Since it is located above, the sheet whose leading end is released slides down onto the sheet placing table under its own weight.

The reverse rotation of the lower separating roller 5 corresponds to the time when the lifting mechanism 13 is operating. In other words, if a large amount of sheets remain on the sheet mounting table 1,
The drive motor 14 rotates for a short period of time and then stops; however, if there are few remaining sheets, it takes time to lower the sheet mounting table, so the drive motor 14 rotates for a relatively long period of time.

In the present invention, a time lag is provided by the rotation transmission delay mechanism between the start of rotation of the drive motor 14 and the start of reverse rotation of the lower separation roller 5, and a time lag is provided by the rotation transmission delay mechanism.
7 is increased in speed and transmitted to the lower separation roller 5, even if the rotation time of the drive motor 14 is short, the sheet held between the lower separation roller 5 can be released. can provide a sufficient rotation angle. Therefore, when the housing of the paper feeding device including the sheet loading table is pulled out, the sheet is not held between the upper separation roller 4 and the lower separation roller 5.

[Brief explanation of the drawing]

Fig. 1 is a side view showing only the main parts of an example of a paper feeding device to which the present invention is applied, Fig. 2 is a side view of the main parts showing an embodiment of the present invention, and Fig. 3 shows the main parts of the reverse rotation control mechanism. FIG. 4 is an exploded perspective view and a front view showing the same operation. 1...Sheet loading table, 3...Sheet sending roller, 4...Separation upper roller, 5...Separation lower roller,
8... Regulation member, 13... Lifting mechanism, 14... Drive motor, 28... Speed increasing gear train, 30... Control gear.

Claims (1)

[Scope of Claim for Utility Model Registration] A sheet loading table that can be raised and lowered to stack sheets, a sheet loading mechanism that lifts and lowers the sheet loading table, and the topmost layer of a bundle of sheets placed on the sheet loading table. a vertically movable sheet delivery roller that is in contact with the sheet and sends out the sheet in the sheet feeding direction; a regulating member that regulates the lower limit of the sheet delivery roller; and a downstream side of the sheet delivery roller in the sheet feeding direction. a separation roller which is arranged at the top and rotates in the same direction as the sheet feeding roller; a lower separation roller which is in contact with the separation roller; A lower separation roller drive mechanism including a one-way clutch that rotates in a direction opposite to the feeding direction, and a rotation transmission delay mechanism that constitutes a part of the lower separation roller drive mechanism, a driving rotary body having an engaging protrusion in a portion thereof, which rotates reciprocally in conjunction with the vertical movement of the sheet mounting table; and a driving rotary body that is paired with the driving rotary body and located within the rotation path of the engaging protrusion. A rotation transmission delay mechanism is provided, which includes an engaged protrusion and a rotated body that rotationally drives the lower separating roller, and transmits the rotational force when the elevating mechanism lowers the sheet mounting table to the sheet mounting table. A paper feeding device characterized in that the paper feeding device transmits the information to the lower separation roller after a predetermined time delay from the timing at which the lowering of the placing table starts.